This application is based on and incorporates herein by reference Japanese Patent Application No. 2002-266944 filed on Sep. 12, 2002.
1. Field of the Invention
The present invention relates to a vapor compression refrigeration system and more particularly to an ejector cycle, which uses an ejector as a depressurizing means.
2. Description of Related Art
As is known in the art, an ejector cycle is one type of vapor compression refrigeration system, in which refrigerant is depressurized and is expanded by an ejector to draw vaporized refrigerant from an evaporator, and the expansion energy of the refrigerant is converted into corresponding pressure energy to increase intake pressure of a compressor. One such an ejector cycle is disclosed in, for example, Japanese Unexamined Patent Publication No. 5-149652.
As is disclosed in Japanese Unexamined Patent Publication No. 5-149652, liquid phase refrigerant, which is separated by a gas-liquid separator, is circulated to the evaporator, which serves as a low pressure side heat exchanger, through pumping action of the ejector (see JIS Z8126 Number 2.1.2.3). However, a portion of the liquid phase refrigerant outputted from the gas-liquid separator can absorb heat from the surrounding atmosphere, in which a refrigerant pipe for conducting the refrigerant from the gas-liquid separator to the evaporator is placed, so that the portion of the liquid phase refrigerant can be vaporized before entering into the evaporator.
When the refrigerant (two phase refrigerant), which is separated into two phases, i.e., the vapor phase and the liquid phase, is supplied to the evaporator, the amount of refrigerant evaporated in the evaporator is reduced in comparison to the refrigerant, which is entirely in the liquid phase. Thus, heat loss, such as a reduction in the refrigeration capacity (heat absorbing capacity) of the evaporator, occurs.
Furthermore, the density of the liquid phase refrigerant and the density of the vapor phase refrigerant are substantially different from one another. Thus, in the evaporator, a flow path of the vapor phase refrigerant and a flow path of the liquid phase refrigerant are substantially separated from one another. As a result, in the evaporator, one location may have a relatively high vapor phase refrigerant content, and another location may have a relatively high liquid phase refrigerant content.
Thus, the refrigeration capacity may vary from place to place in the evaporator. As a result, the surface temperature may vary from place to place in the evaporator. This results in inappropriate temperature distribution.
The present invention addresses the above disadvantages. Thus, it is an objective of the present invention to provide a novel vapor compression refrigeration system. It is another objective of the present invention to reduce heat loss in a low pressure side of a vapor compression refrigeration system.
To achieve the objectives of the present invention, there is provided a vapor compression refrigeration system that transfers heat from a low temperature side to a high temperature side. The vapor compression refrigeration system includes a compressor, a high pressure side heat exchanger, a low pressure side heat exchanger, an ejector and a gas-liquid separating means. The compressor draws and compresses refrigerant. The high pressure side heat exchanger releases heat from high pressure refrigerant discharged from the compressor. The low pressure side heat exchanger vaporizes low pressure refrigerant. The ejector increases intake pressure of the compressor and includes a nozzle arrangement and a pressurizer arrangement. The nozzle arrangement depressurizes and expands high pressure refrigerant supplied from the high pressure side heat exchanger. The pressurizer arrangement draws vapor phase refrigerant, which is vaporized in the low pressure side heat exchanger, through use of high speed refrigerant flow discharged from the nozzle arrangement and converts expansion energy of the refrigerant discharged from the nozzle arrangement into pressure energy. The gas-liquid separating means is for separating the refrigerant discharged from the ejector into vapor phase refrigerant and liquid phase refrigerant. The gas-liquid separating means has a vapor phase refrigerant outlet for outputting the vapor phase refrigerant and a liquid phase refrigerant outlet for outputting the liquid phase refrigerant, and the vapor phase refrigerant outlet and the liquid phase refrigerant outlet of the gas-liquid separating means are connected to a refrigerant inlet of the compressor and a refrigerant inlet of the low pressure side heat exchanger, respectively. At least the gas-liquid separating means and the low pressure side heat exchanger are arranged in a common casing.